-or1
/ə/ /ɔː/suffix
(Forming nouns) denoting a person or thing performing the action of a verb, or denoting another agent: escalator governor resistor
Origin
From Latin, sometimes via Anglo-Norman French -eour or Old French -eor (see also -ator).
-or2
/ə/suffix
Forming adjectives expressing a comparative sense: junior major
Origin
Via Anglo-Norman French from Latin.
-or3
/ə/suffix
Forming nouns denoting a state or condition: error pallor terror
Origin
From Latin, sometimes via Old French -or, -ur.
-or4
/ə/suffix
US form of -our2.